9.8 List various types of isomerism possible for coordination compounds, giving an example of each.


 

(a) Geometric isomerism:
This type of isomerism is common in heteroleptic complexes. It arises due to the different possible geometric arrangements of the ligands. For example:

 

 (b) Optical isomerism:
This type of isomerism arises in chiral molecules. Isomers are mirror images of each other and are non-superimposable.

(c) Linkage isomerism: This type of isomerism is found in complexes that contain ambidentate ligands. For example:
Co(NH3)5 (NO2)CI2  and  Co(NH3)5 (ONO)CI2

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(d) Coordination isomerism:
This type of isomerism arises when the ligands are interchanged between cationic and anionic entities of differnet metal ions present in the complex.
Co(NH3)6 Cr(CN)6 and Cr(NH3)6

(e) Ionization isomerism:
This type of isomerism arises when a counter ion replaces a ligand within the coordination sphere. Thus, complexes that have the same composition, but furnish different ions when dissolved in water are called ionization isomers. For e.g.,
Co(NH3)5 5SO4 Br and Co(NH3)6BrSO4
(f) Solvate isomerism:
Solvate isomers differ by whether or not the solvent molecule is directly bonded to the metal ion or merely present as a free solvent molecule in the crystal lattice. 

Cr(H2O)6CI3 ,Cr(H2O)5 CI2 .H2O and Cr(H2O)5 CI2.2H2O

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